372 Hydrogen Ions in Biological Fluids [April 



sociable oxygen Compounds, electromotive constancy is not attained 

 until the moment when the layer of liquid into which the electrode 

 projects is completely reduced. In such cases it may be useful, by 

 saving time, to apply the Suggestion of Michaelis,^^ namely, to let 

 the electrode just touch the surface of the liquid. 



I am of the opinion that by following the lines indicated above, 

 we shall be able to measure the hydrogen-ion concentration of bio- 

 logical fluids in many cases where it has hitherto been considered 

 impossible, or where we have had to be satisfied with rough approxi- 

 mations. There are undoubtedly numerous questions in biology 

 and pathology which these improvements in method may help to 

 solve. 



" Michaelis : Loc. cit. 



